Pneumatically driven tool for marking, carving, and light hammering



May 2, 1961 H R. KLENCK 2,982,255 PNEUMATICALLY DRIVEN TOOL FOR MARKING,CARVING AND LIGHT HAMMERING Filed Oct. 23. 1958 lNl/ENTOR HERBERTR/CHARD KL ENCK 8V ATTORNEY V States 'ice 2,982,255 v PNEUMATICALLYDRIVEN TOOL FOR MARKING,-

. ,CAR'VING, AND LIGHT HAMNIERING. Herbert Richard Kinda-Richmond Hill,N.Y., assignor to Pneumatic Tool Sales & Repair Co. Inc., Long lsl landCity, N.Y., a corporation of New York Filed on. 23, 1958, Ser. No.769,169

" 9 Claims. Cl. 121-25 The instant invention relates to a pneumaticallydriven tool, for example for marking hard surfaces, scaling paint,dental work, carving of all types, pin driving, or any work requiringlight hammerblows, of whichthe vibratingi point has an extremely shortstroke at ahigh frequency. r a i object of the vention isto provide, aminiature pneumatic tool having a high stroke frequency and a shortstroke of such proportions that it can readily'be held and operated inonehand. 7

' A' further object is to provide a miniature pneumatic tool of whichthe casing is of such weight as substantially not to transmit vibrationsto the users hand in operation andis. of such configuration astobereadily held.

A further object is to provide a pneumatic tool for onehand operation ofwhich the air valve may readily be opened and closed by a finger,usually. the thumb or index finger, of the hand in which the tool isheld while the tool is so held in working position.

The features, and objects, of the invention, will readily be understoodfrom the following detailed description of an illustrative embodimentwhen read in conjunction with the annexed drawing in which the solefigure is a longitudinal section along the axis of the miniaturepneutherefor.

The housing of the tool comprises two cylindrical sleeves 1 and 2 eachintegral with a hemispherical region matic tool of my invention andofthe air supply valve 3 and 4, of which the flat bases arebolted'airtight to.

each other by a plurality of bolts 5, an annular internal rim 6extending from a cylindrical bore 7 with hemi spherical region 4 into acylindrical bore 8 of hemispherical portion 3 and concentric with bore 7but of slightly larger diameter to provide a tight fit of rim 6 intobore 8. The housing is .of a heavy metal, for example,steel,

brass, ferrous or non-ferrous metals, and the apertures for bolts aresufficiently deep that only the smooth spherical surface of housingportions 3 and 4, is encountered with the bolts properly tightened. Inthe sleeve portion 1 .of' the housing a longitudinal bo=re 9 isconcentric with bore 8 andconnects therewith beyond? the annularshoulder 10. An elongated rod 11 slidable within bore 9 has integraltherewith a disc,1 2;whih' is a snug sliding fit in bore 7. Acompression spring 13 encircles the portionof the rod"11 between theshoulder 10 and disc 12.against which it is braced at its respectiveends. To allow for the decrease in the internal diameter of the turns ofspring 13 when the spring is compressed .a portion '14 of the length ofrod 11 adjacent to the face of disc 12 and about which the spring 13 ispositioned is somewhat undercut. The free end of rod 11, which at alltimes extends from the end of sleeve 1 may be formed as the internalmembers of a chuck 15 by which a tool steel, or similar hard material,point 16 is held, as shown, or may be directly formed as such point,with which the scribing, etc., is had, as below explained.

The portion 17 of rod 11 to the other side of disc 12 Pat ented 2, 1961is a snug sliding fit in a bore 18 concentric with bore 7, and of anappreciably smaller diameter, and has a flat exterior surface 19 betweenits cylindrical free end-region" 20 and the disc 12. The flat surface 19is obtained by removing an arcuate portion of the-cylindrical surface ofrod portion 17, as by milling. The length of the flat surface 19,longitudinally of the rod '11 is such that with the disc 12 against theshoulder 21 formed in bore 7 bythe reduced diameter of bore 18, rod endportion 20 is within bore 2 2, concentric with and of a larger di-vameter than bore 18, a distance of a length of about A5 of the flatsurface 19. The air supply duct 23 opens into the bore 22, and thus withcompressed air inflowing such air will flow from bore 22 through openingd between the wall of bore 22 and flat surface 19,and against disc 12.Rotation of disc 12 primarily for locking the piston while tighteningthe chuck, is prevented by the pin 24 integral with the hemisphericalhousing portion 4 extendingjthrough an aperture 25 through disc 12-in aclose slidingfit, pin 24 being of a length ade-- figure), compressingspring 13 with the air betweenthe disc 12 and in bore 8 exhausting tothe atmosphere through a pair of exhaust passages 27. In an alternativeembodiment, the pin 24 is press fitted through the disc 12, and is of alength to slidein two bores, not shown, aligned therewith in sleevehemispherical regions 3 and 4 respectively, thus avoiding all leakage ofair between the pin 24 andaperture 25. It will be noted such drivecontinues until the cylindrical end 20 of rod portion 17 enters bore 18when no further air can flow through bore 18. With the fair inflow todrivedisc 12 stopped,

spring 13 now takes .over and tends to restore to its original state'from its now compressed state, driving the disc 12.to the left, untilsuch compression of the spring is released, the spring expands, and therod end 20 again is in bore 22 tofuncover the above stated lengthportion d of flattened rod-surface 19, when the cycle begins anew.

The air inlet duct 23 includes valve member 28 slidable a predetermineddistance on the exterior of duct 23 and between an end nipple 29 on theduct 23 and the end face of tool sleeve 2. The slidable valve member 28has an axially extending groove 30 in its outer cylindrical surfaceprocided with two spaced detents 31 and 32 in its bottom surface.

distance from its free end as to be engaged to detent 31 when theslidable valve member 28 strikes nipple 29 and closes the airduct 23,and with detent 32 when the slidable valve member 28 strikes sleeve '2and opens the air duct. Within a hollow interior region 35 defined bythe slidable-valve member 28, agate member 36 is supported spaced fromthe walls of the hollow interior so that with slidable member 28 in theposition shown in the figure, the gate member 36 is spaced from theopenings of duct 23 into interior region 35, thus permitting passage ofair from a source connected to nipple 29 to flow into the tool, whilewith the slidable member 28 pushed to strike the nipple end face 29,detent 34 of spring 33 enters detent 32, to hold gate member 36 againstthe source opening of duct 23 into interior region 35, thus shutting offthe air supply. It is to be noted A flat spring 33 is aflixed at. oneendto the nipple 29 and has a detent 34 at such;

: 3 that with the entire assembly held in the usershand with point 16against the work surface to be scribed, or otherwise worked upon, andthe spherical portion 3, 4 grasped by the fingers, the slidable airvalve member 28 may readily be pushed to open and closethe air duct 23by a simple and slight axial movement of a finger;

By way of example of the magnitudes involved, the total weight of'apractical embodiment of the miniature pneumatic tool of my invention is8% ounces, the spherical diameter is 1% inches, the diameter of bores 9and 18. is inch, of bore 8 is inch, of bore 7 is inch, the distance ofshoulder 10 from shoulder 26 about inch, the length of flat surface 19about inch, of disc 12 /4 inch, and the diameter of rod 11, includingportion 17, 4 inch. With an air pressure of 40 to 60 lbs., and a springpressure of from about 8 to 10 lbs., I obtain. frequencies of theiorderof, for example, 2500 strokes per minute at an air pressure of 25 lbs.per square inch. It is furthermore noted that the vibrations of thepoint 16 with rod 11 and disc 12, are not transmitted to the handof theuser in that the inertia of the housing is such as to absorb vibrations,thus avoiding any un-. pleasant and tiring sensation to the user.

It is expressly understood that neither as to the form of the aboveembodiment nor as to thedimensions of any of its elements, do Ilimitmyself thereto, and that modifications thereof will occur to theskilled worker in the art which will still be embraced and includedwithin the scope and spirit of my invention.

What I claim is:

1. A pneumatic tool comprising a casing defining an internal boretherethrough of an increased diameter at an intermediate region, aformed piston reciprocable in the bore having an enlarged portion in theintermediate bore region and an end thereof projecting externally thecasing, spring means acting against the face of the enlarged pistonportion the nearer to its projecting end, valve means integral with thepiston for applying compressed air from a source to the opposite face ofthe enlarged piston portion to drive the piston and to cut oflE thecompressed air at the end portion of the air driven movement of thepiston to permit the spring means to return the piston to the positionin which the valve means is open, and an air supply passage of adiameter larger than the internal bore of the casing in which the end ofthe piston having the valving means is positioned connects in axialalignment with such casing internal bore, the spring means biasing thepiston to project such piston end into the air supply passage apredetermined distance to permit flow from the air passage through thebore and against such opposite face of the enlarged piston portion.

2. The pneumatic tool according to claim 1 in which the valving meanscomprises a groove in a peripheral region of the piston end portion fromsuch opposite face of its enlarged portion to adjacent the end of thepiston facing the air supply passage.

3. The pneumatic tool according to claim 2 in which the formed piston isan elongated rod and its intermediate portion is a disc, and the valvingmeans is a longitudinal groove in its exterior cylindrical surfaceextending from the disc a predetermined distance to a point spaced fromthe end region of the rod facing the air supply passage.

4. A pneumatic tool comprising a hollow casing defining a longitudinalstepped bore therein of which the end portions are of predetermineddiameter and an inter- 4 mediate portion of an enlarged diameter, anannular shoulder to each side of and spaced from the enlarged diameterbore portion at which the bore diameter is intermediate thepredetermined and the enlarged diameters, an elongated cylindrical rodhaving end regions slidably fitted into the bore portions of thepredetermined diameter, a disk integral with an intermediate region ofthe elongated rod and slidably fitted in the enlarged diameter portionof the bore, one end of the bore being adapted for connection to asource of compressed air, a tool being attachable to the end at theother end of the bore and extending from the bore, a spiral springencircling the rod braced between the disk and the annular shoulder tothe tool-bearing side of the rod, and a planar surface formed in thecylindrical surface of the rod extending longitudinally from the face ofthe disk opposite that against which the spring bears to a region of therod adjacent its end toward the source of compressed air so that. theplanar surface extends a predetermined distance into the bore portion ofintermediate diameter to the air source side of the bore with the springforcing the disk to that end of the enlarged diameter bore to permitcompressed air to flow through that end bore of predetermined diameterand against the disk to propel the disk againstthetension of the springat least the predetermined distance to seal such end bore and permit thespring to restore the disk to its original position wherebyreciprocating motion is imparted to the rod and disk.

5. The pneumatic tool according to claim 4 for onehand operation inwhich end of the casing defining the end bore for connection to thesource of compressed air is provided with a slide valve for one fingeroperation to one of two positions in one of which the source isconnected to and in the other of which the source is disconnected fromsuch end bore.

6. The pneumatic tool according to claim 4 in which a fixed axial guidemeans cooperating with the disk prevents rotation of the disk about itsaxis.

7. The pneumatic tool according to claim 6 in which the guide meanscomprises a rod extending from at least one annular shoulder the lengthof the intermediate portion of the bore and a close-fitting aperturedefined by the disk.

8. The pneumatic tool according to claim 5 in which the casing is oftwo-part construction bolted to each other, the regions of each part attheir bolted portions being hemispherical in shape and of sufiicientweight to dampen transmission of the reciprocatory motion of the rod anddisk tothe hand of the user.

9. The pneumatic tool according to claim 5 in which the slide valve hasan internal gate member which in the closing position of the slide valveblocks the air passage from the source and in the open position isremoved from the air passage to permit air flow around it into the endbore of the casing, the body of the valve being provided with a pair ofnotches, and a spring latching member mounted on the exterior wall ofthe air passage and adapted to engage one of the pair of notches whenthe valve body is pushed away from the casing to lock the gate member inthe closed position and to engage the other notch when the valve body ispushed against the casing to lock the gate member in the open position.

References Cited in the file of this patent UNITED STATES PATENTS2,668,518 White Feb. 9, 1954

